Frog Dissection

The mouth, nostrils, and eyes

1. Nictictating membrane-

Protects eyes (similar to an eyelid)

2.Tympanic membrane – the ear drum

- Collects sound waves

- Allows frogs to hear in water

Examine the Mouth

• 1. Maxillary Teeth – (along inner edge of upper jaw)

• 3. Vomerine Teeth – (roof of mouth)– Teeth are used to hold onto caught prey, do not use them to chew, they

swallow prey whole!!

• 6. Opening to Eustachian tubes

• 2. internal Nares

• 8 Glottis

• 10.Internal Nares –internal nostril openings on either side of the vomerine teeth.

• 11.Eustachian tube openings –connenct mouth cavity and the tympanic membrane– Help to equalize

internal ear pressure

– If the frog is male, these are near the openings to the vocal sacs which allow male frogs to make sounds

• 50.Vomerine teeth

Internal Structure -Female

• 31.Eggs • 32.Oviduct – tubes which carry the eggs after they have

been made

• 22 – Eggs• 18 – Liver –

– 3 lobed structure that produces bile for lipid digestion and starch

– Food does not pass through, but blood does

– Still considered as part of digestive system

• 9- Stomach• 6 – Ventricle of heart• 12 – small intestine

The Heart – 3 chambered structure

• 34.Conus arteriosus

• 35.Atrium

• 36.Ventricle

19 – Pericardium – membrane that surrounds the heart.

Heart – Circulatory System

• 1. Ventricle  • 2. Right atrium  • 3. Left atrium 

• 4. Sinus venosus – Triangular sac

underneath the heart  – Veins from all over the

body empty here before going into the right atrium

– Part of circulatory system

The Lungs

• Lungs – 2 sac like structures on either side of the heart– Collect oxygen from air and transfer it to blood

supply– Part of respiratory system

7- Right Lung and 8 –Left Lung

Digestive system• 16.Small intestine

– At lower end of the stomach

– Breaks soupy mixture from stomach into usable nutrients using bile from liver and enzymes from the pancreas

• 17.Liver - • 18.Large intestine

– Collects waste from tissues and wastes that could not be absorbed by the small intestine.

• 19.Stomach – secretes digestive juices to break down whole food swallowed by the frog into a soupy mixture

• 26.Spleen –filters improperly functioning blood cells; circulatory system

• 29.Teste

10 – pancreasSecretes enzymes into small intestine

19 – stomach54 - pancreas

Digestive system• 16.Small

intestine

• 19.Stomach

• 33.Gall bladder

11- Pylorus- muscular valve between the stomach and small intestine

23 – KidneyLocated in either side of the spine, near the dorsal side; filter blood and urine that drains into the urinary bladder;

excretory system

• 23 & 24 Kidneys• 21 – Fat Bodies• 27 – Urinary Bladder

– urine travels from the kidneys, down tubes called ureters to this bladder where it is stored until emptied through the cloaca.

• 21 – Fat Bodies– Attached near

kidneys– Store fat for

nourishment for the gametes

– Much larger and more abundant in females

• 22-Testes– Small, oval

structure underneath kidneys

– Sperm travels through the kidneys, down the ureters and out the cloaca.

• 23 & 24 Kidneys